Pre-blended Portland CementPlaster and Silos

Jerry L. Pozo - CSI, CDT, BSBMI Products

MAY 16, 2013

Introduction

• Although it goes by many names, from Portland cement plaster toHard Coat Stucco, everyonehas seen, worked, or lived in a stucco-clad structure.

As its popularity rises, proper specification and installation becomesmost critical for ensuring long-term performance and crackresistance.

Today’s presentation will help you better understand:• Field-mixing – Concentrates - Premixed products• Issues affecting the plaster mix• Environmentally-friendly silos and mixers• Industry Personnel• Plastering-related issues• and….more.

IntroductionFrom the Late 1990’s to Present

Through Research + Development, plaster & products to renderexceptional properties such as:

• increased hardness• better flexibility to prevent cracking• water resistance (yet remaining vapor permeable)• better workability• faster curing• premixed materials• lamina/level coat• faster applications• wide array of finishes• and more…….have been developed.

Introduction

• There are 3 Types of Delivery Methods forPortland Cement Plaster

• Traditional field-mix• Concentrate• Premixed - Option for various Silo-mixers

Lets Take a Look

• Field-Mixed Plaster

Field Mix• Sand piles are messy and prone to contamination• Many jobsites do not have room for a pile• Some locations and/or jurisdictions have regulations on storm water

runoff• Builders can face huge fines if caught allowing materials to run into

storm drains

Problems: Impurities of Aggregates

• Many contractors order plaster sand with no concern for its purity– Should be measuring it on every job

• Many local plaster sands test above 70 and 80 and should producesolid plaster

• Lower SE sands require more water, which leads to more shrinkagecracking, lower strength, and lower density

4A: Plastic cement with a SE=49sand (9 gallons water)

4D: Plastic cement with a SE=86sand (6.75 gallons water)

Problems: Impurities of Aggregates

• ASTM D2419 is the Standard Test Method for Sand-equivalent Value ofSoils and Fine Aggregate (SE) is an easy and fast way to test for impurities

• Add roughly equal parts sand and water, shake in bottle to put insuspension

• Allow to settle 20 minutes, measure what percentage of aggregate is sand,the higher % is better

1/8” silt,

2-1/2” sand

SE=2.5/2.675SE = 93

5/8” silt,

1-1/4” sand

SE=1.25/1.875SE = 67

Sieve Analysis orGradation Test

• This ASTM E-11 procedure is used to assess the particlesize distribution

• It is often of critical importance to the way the materialperforms in use

• This being a simple technique of particle sizing is themost common

Problems: Impurities of Aggregates

• Clays– Absorb water from the mix,

then shrink as they dry andcause cracking

– A little clay helps plaster “slip”through the hose whenpumped and improvesworkability, but can beproblematic if too much used

• Dark aggregate:– Dark spots can peek through

light colors in finish coat andmake plaster look dirty

Problems: Impurities of Aggregates

• Iron– Small amounts of iron

contamination in the sand canlead to rust spots

– Costly to repair• Bond-breakers

– Oils can affect bond betweencoats

Problems: Sand Gradation

• Plaster sand should meet the requirements of ASTMC897, (not ASTM C144) which specifies a size profile of:

SieveStandard

Natural SandNatural Sand Manufactured SandManufactured SandMax.Max. Min.Min. Max.Max. Min.Min.

No. 4No. 4 00 00 00 00No. 8No. 8 1010 00 1010 00

No. 16No. 16 4040 1010 4040 1010

No. 30No. 30 6565 3030 6565 3030No. 50No. 50 9090 7070 8080 6060

No. 100No. 100 100100 9595 9090 7575

No. 200No. 200 100100 9797 100100 9090

Melding Together Properly

All the same size has toomany voids

•Variation in sieve

sizes (Gradation)

The Sand Issue

• Problems with Today’s Sand:• Variation of particle sizes• Lack of quality control at jobsite• Too much sand affects integrity of

mixture• Issue of sand piles on jobsites,

cannot accommodate space,contamination, clean-up

• On site injury due to repetitiveshoveling and heavy lifting

• Resolution:• Preblended basecoat mixes were

developed to solve thesechallenges

Advantages ofPreblended Products

• High quality, consistent, premixed plaster:– Use dried and graded sand that complies with ASTM standards and

should not have any of the problems with impurities or gradation– Does not rely on contractor to accurately measure the various

plaster materials– Goes through manufacturer’s Q.C./Q.A process

• Reduces cracking thanks to proper proportions andperformance additives

• Consistent appearance of finish• Cleaner overall jobsite• Complies with storm water runoff requirements• Less room devoted to plastering footprint on jobsite• Less prone to contamination on jobsite

Bagged Products

• Stucco manufacturers all offer preblendedbase coat products– Scratch and brown coats– Continuous insulation base coats (one coat)

• Some products have different attributes– Additives for pumpability, water reducers, etc.– High early strength for accelerated work

scheduling, cold weather– Fibers for crack-reduction, added strength

• Lowest cost next to field-mixed base coats

Concentrates

Silo and Separate Mixer

Manual Labor

10 Ton Mini Silo w/ inline mixer

Filling the Mini-Silo

Mini Silo Servicing Project

Options for Premix

• Premixed plaster comes in a 80-90lb. bag of factory-blendedmaterials

• Some manufacturers offer premixed Super Sacks 2,500 – 3,000 lbsusing a mini-silo

• Another, an environmentally- friendly 30 ton silo/mixer

What is an ICC Report?

LEED Accreditation Points

• These are categories which most Premixed & Engineered Plastercan earn LEED accreditation points for a project under Material &Resources:

• Storage & collection of recyclables• Construction waste reuse or recycling• Reuse of materials• Use of local materials and fabrication (within 500 miles)• Airborne dust collection system and air quality (silos)• Storm drain pollution prevention program

Newest Plaster Manual

2012• Plaster Assemblies Manual

• www.tsib.org•

• (714) 221-5530

Plaster Resources

• PLASTER RESOURCES

• 2012 Plaster Assemblies Manual by TSIB (MUST HAVE)• 2010 Plaster Textures & Acrylic Finishes by TSIB (MUST HAVE)• 2008 Selected ASTM Standards by TSIB• 2007 Portland Cement Plaster (Stucco) Manual by PCA• 2007 Builders Guide to Stucco – Lath and Plaster by Max Schwartz

with Walter F. Pruter• 1997 Portland Cement Plaster/Stucco Resources Guide by the

Northwest Walls & Ceilings Bureau, or other local plastering industryoffices (OUTDATED)

• 1997 Exterior Insulation and Finish Systems Design Handbook byRobert G. Thomas

Our Industry Bureaus• Plaster Industry Bureaus and Directors:

• Mark Eisenmann NWCB 206-524-4243• Terry Kastner NWCB 206-524-4243

• James Johnson WACA 415- 519-9963• Frank Nunes WACA 925-600-0475

• Michael M. Logue TSIB 714-256-1244• Bryan Stanley TSIB 714-256-1244• Mark Fowler WWCCA 714-221-5520

• Norma Fox SMA 949-640-9911

• Melody Shupe APLC 619-749-1667

• Robert Campbell WWCCA/LV 702-319-2717• Albert Carrillo WWCCA/ AZ 480-829-9133

Advantages of Silos

Advantages of Silo Systems

• #1 BENEFIT: Quality Control and Quality Assurance

• Preblended materials to exact ASTM C 926 Standard• Material contributes to LEED accreditation points• Greater productivity and efficiency of labor force• Inherently safe delivery method - lessens contractor liability• Silo/mixer/pump function as single unit making for a efficient delivery system and cost

effectively brings Portland cement plaster to their point of use• All materials are weighed prior to blending assuring consistency• Uniform color throughout the job• No freezing of product in winter, no water damage to products• Environmentally-friendly, re-useable silos, no dust or disposal of bags, no waste of

product

What Our Industry is Saying

• “Once you adjust the water flow to the silo-mixer, the mix will come out consistentlyall day long. You just push a button on and off and it takes the workload and stressof your hod carrier”

• “One person does the work of many other laborers and their health is much better notshoveling sand all day long and lifting heavy sacks. This system prevents backinjury.”

• Due to environmental concerns, silos cut down or eliminate any dust which is anadvantage since it is a more controlled environment.”

• “The only time you see the product is when it comes out of the mixer in wet form.”• “One of the biggest problems in the field has been consistency. Since the product is

premixed, it takes away that issue of uncertainty and not having the right amount ofeach ingredient”

• “You get the right mixture every time. There is no way you can go wrong with it.”• “The silo delivery system for plaster (in my opinion) is the future. Field mixed

products are an inaccurate science and with the level of scrutiny our contractors areunder on projects, this system is perfect.”

Whatchawannano?

• Jerry L. Pozo, CSI, CDT, BS• Mobile (408) 595-2031

• Office Phone/Fax (530) 885-6828• Email: jpozo@bmi-products.com